Brad Butler, CEO of Halloween Express, said buying decisions start immediately after the holiday and continue through March. “So there’s ample time to have the product made and shipped via the ocean to the U.S. market,” he said.

“It’s not possible to predict with certainty what will be popular or trendy. I wish we could,” he said.

Licensing restrictions also constrain retailers from quickly making costumes of popular celebrities or movie characters, he said. Halloween Express sells more than $50 million a year in costumes and other items online and at its 130 seasonal store locations across the U.S.

They can get around that by making celebrity Halloween “kits” using items the actor, singer or politician may be known for and packaging them together for sale.

“The thrown-together celebrity kits usually are done using look-a-like pieces or pieces that closely resemble something the celebrity was known for,” Butler said. “In Michael Jackson’s case, a sequin glove was easy enough to use to get the idea across.”

Disguise Costumes, which bills itself as the world’s leading costume company, licenses ideas from Hasbro, Disney and other movie studios so its turnaround time is a lot slower. However, when 2012 presidential candidate Mitt Romney proposed to take away government funding for PBS, home of popular children’s show “Sesame Street,” demand for Big Bird costumes rose, said marketing director Bernice Nesbit.

Some of the company’s most popular costumes this year are characters and items from the summer blockbuster hit “The Incredibles 2.”

Smaller, independent Halloween stores also try to stay on trend.

When Hugh Hefner died in September 2017, Halloween Adventure in New York placed an order for Playboy costumes the next day but then had a hard time keeping them in stock, head buyer Jodi Lewis said.

After the 2014 Ebola outbreak in Africa, costumes of hazmat suits, which were worn by the medical staff treating patients, went viral over Halloween. And, of course, there was the inevitable sexy version.

Generic costumes like hazmat suits, which become trendy because of the news, are easier to produce because of fewer licensing issues, according to Butler.

Many retailers have not yet seen a clear trend this year. Lewis, for example, noted that pineapple costumes are flying off the shelves at her store.

“We don’t know why,” she said, but she noted a rising trend in carving pineapples instead of pumpkins.

Retailers may not always be able to accurately predict what consumers are looking for, but they try to do their best.

Ultimately, Butler said, it “comes down to a mixture of intuition, historical perspective, experience, monitoring pop-culture trends and news events and some good ole’ fashion luck.”